The present invention relates to an apparatus for effecting a fine movement of an object by making use of impact produced by a piezoelectric/electrostrictive element.
FIGS. 1 and 2 illustrate known apparatus for effecting a fine movement of an object by a mechanical means. Referring first to FIG. 1 which illustrates a first type of known apparatus for effecting fine movement, a moving member 1 having a mass M is provided with an electromagnetic device. On the other hand, a coil 3 as an inertia member is supported on the moving member through a buffer member 2 such as a spring. In operation, the electromagnetic device produces an electromagnetic impacting force which is caused by repulsion and collision of the coil 3, thereby effecting fine movement of the moving member.
Referring now to FIG. 2 schematically illustrating a second type of known apparatus, a moving member 5 incorporates an electromagnetic device capable of imparting an impact to the moving member 5. The moving member 5 has legs constituted by a permanent magnet so that the moving member 5 is moved by a small amount by impacting force produced by the electromagnetic device, while being attracted to the surface of a base on which a groove 8 is formed.
The moving apparatus relying upon impacting electromagnetic force essentially requires a circuit which generates a magnetic field by means of a coil. The coil has to have certain volume and surface area in order to attain a high efficiency while avoiding generation of heat, magnetic field or electromagnetic noise. Furthermore, both types of known apparatus mentioned above suffer from a common disadvantage in that noise and dust tend to be generated due to collision of the inertia member.